Without wading through a hardware compatability list, it looks good to me.
Just a couple of questions: Is that modem an external modem (or, at least, a *full* modem)? Winmodems *can* be difficult to get working in Linux, although Mandrake, like most distros, now recognizes and configures many of them automatically.
Do you know the *real* manufacturer of your video card? It will probably configure just fine during installation, and you can guess what it is based on the final xorg.conf file. If it is ATI- or nvidea-based, you can get proprietary video drivers to improve performance.
Basically, I would be willing to give Mandrake a shot on that machine.